Gc3200

Catalytic activity tests for the DRM were performed using a flow-type reactor, MicrotracBEL BELCAT II. Prior to reaction, the catalyst (100 mg) was loaded in a tubular reactor (inner diameter = 7.5 mm) and fixed with quartz wool on both sides. Then, the catalyst was reduced by H₂ at 30 mL/min flow at 450 °C for 2 h. The DRM was conducted at 550 °C under a mixed gas stream of CO₂/CH₄/N₂ = 10/10/5 (v/v/v) with a total gas flow rate of 25 mL/min. The temperature of the reactor was maintained at 550 °C for 15 h. The gaseous products were analyzed using a gas chromatograph (GL Sciences GC3200) with an active carbon column equipped with a TCD.
The CH₄ and CO₂ turnover frequencies (TOFs) were calculated by the moles of CH₄ or CO₂ converted per second per the moles of catalysts with the following equation: $$\text{TOF}=\frac{N(\text{gas})}{N(\text{catalyst})}\times \text{conversion}$$ where N (gas), N (catalyst), and conversion represent gas flow rate (mol/s), amount of catalyst (mol), and conversion of reactant gas, respectively.

The exhaust gas composition from the cells in the open-circuit state was analysed by gas chromatography (GC; GC-3200, GL Sciences) with thermal conductivity detection. As the carrier gas, Ar and He were used for the analysis of H₂ and the other gases in the exhaust gas, respectively. Quantification of the results was performed using a calibration curve. The inorganic components of the gas and methane were detected using an active carbon column at 50°C, while the organic components were detected using a Porapak Q column at 150°C. Measurements from the two different columns were calibrated using the measured values of the same concentration of methane. The peaks derived from steam were removed from the exhaust gas of the cell using a cold trap because steam had a broad GC peak with strong intensity. The amounts of remaining H₂O were estimated based on the theoretical mass balance.